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      Astronomy Picture of the Day
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      <h1> Astronomy Picture of the Day </h1>
      <p>

        <a href="archivepix.html">Discover the cosmos!</a>
        Each day a different image or photograph of our fascinating universe is
        featured, along with a brief explanation written by a professional astronomer.
        <p>
          2011 December 10
          <br>
            <a href="image/1112/PIA15138vestarocks.jpg">
              <IMG SRC="image/1112/PIA15138vestarocks.jpg"
              alt="See Explanation.  Clicking on the picture will download
 the highest resolution version available.">
              </a>
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      <b> Vesta Rocks </b>
      <br>

        <b> Image Credit: </b>

        <a href="http://www.nasa.gov/">NASA</a> /
        <a href="http://www.jpl.nasa.gov/">JPL-Caltech</a> /
        Hap McSween (Univ. Tennessee),
        A. Beck and T. McCoy (Smithsonian Inst.)

      </center>
    <p>

      <b> Explanation: </b>

      <a href="http://photojournal.jpl.nasa.gov/catalog/PIA15138">
        These
        colorful images
      </a> are of thin slices of meteorites viewed through a
      <a href="ap050226.html">polarizing</a> microscope.

      Part of the group classified as HED meteorites
      for their mineral content (Howardite, Eucrite, Diogenite), they likely
      <a href="http://www.psrd.hawaii.edu/Nov07/HEDs-Vesta.html">
        fell
        to Earth from 4 Vesta
      </a>,
      the mainbelt asteroid currently being explored by NASA's
      <a href="http://www.nasa.gov/mission_pages/dawn/main/
index.html">Dawn spacecraft</a>.

      Why are they thought to be from Vesta?

      Because the HED meteorites have visible and infrared spectra
      that match the spectrum of
      <a href="http://www.psrd.hawaii.edu/June09/Vesta.granite-like.html">
        that
        small world
      </a>.

      The hypothesis of their origin on Vesta
      is also consistent with data from
      <a href="http://www.nasa.gov/mission_pages/dawn/news/
dawn20111205.html">Dawn's ongoing</a> observations.

      Excavated
      <a href="ap110919.html">by impacts</a>, the diogenites shown here
      would have originated deep within the crust of Vesta.

      <a href="http://adsabs.harvard.edu/abs/2002aste.conf..573K">Similar rocks</a>
      are also found in the lower crust of planet Earth.

      A sample scale is indicated by the white bars,
      each 2 millimeters long.

      <p>
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          <b> Tomorrow's picture: </b>meteorite central

          <p>
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                  <b> Authors & editors: </b>
                  <a href="http://antwrp.gsfc.nasa.gov/htmltest/rjn.html">Robert Nemiroff</a>
                  (<a href="http://www.phy.mtu.edu/">MTU</a>) &
                  <a href="http://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html"
>Jerry Bonnell</a> (<a href="http://www.astro.umd.edu/">UMCP</a>)<br>
                    <b>NASA Official: </b> Phillip Newman
                    <a href="lib/about_apod.html#srapply">Specific rights apply</a>.<br>
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                        <b>A service of:</b>
                        <a href="http://astrophysics.gsfc.nasa.gov/">ASD</a> at
                        <a href="http://www.nasa.gov/">NASA</a> /
                        <a href="http://www.nasa.gov/centers/goddard/">GSFC</a>
                        <br>
                          <b>&</b>
                          <a href="http://www.mtu.edu/">Michigan Tech. U.</a>
                          <br>


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